Make remaining UI responsive to app mode changes

Signal/src/Loki/View Controllers/BaseVC.swift

@@ -1,5 +1,6 @@
 
 class BaseVC : UIViewController {
+    private var hasGradient = false
 
     override var preferredStatusBarStyle: UIStatusBarStyle { return isLightMode ? .default : .lightContent }
 
@@ -23,10 +24,12 @@ class BaseVC : UIViewController {
 
     override func viewDidLoad() {
         setNeedsStatusBarAppearanceUpdate()
-        NotificationCenter.default.addObserver(self, selector: #selector(handleUnexpectedDeviceLinkRequestReceivedNotification), name: .unexpectedDeviceLinkRequestReceived, object: nil)
+        NotificationCenter.default.addObserver(self, selector: #selector(handleUnexpectedDeviceLinkRequestReceivedNotification(_:)), name: .unexpectedDeviceLinkRequestReceived, object: nil)
+        NotificationCenter.default.addObserver(self, selector: #selector(handleAppModeChangedNotification(_:)), name: .appModeChanged, object: nil)
     }
 
     internal func setUpGradientBackground() {
+        hasGradient = true
         view.backgroundColor = .clear
         let gradient = Gradients.defaultLokiBackground
         view.setGradient(gradient)
@@ -68,7 +71,7 @@ class BaseVC : UIViewController {
         NotificationCenter.default.removeObserver(self)
     }
 
-    @objc private func handleUnexpectedDeviceLinkRequestReceivedNotification() {
+    @objc private func handleUnexpectedDeviceLinkRequestReceivedNotification(_ notification: Notification) {
         guard DeviceLinkingUtilities.shouldShowUnexpectedDeviceLinkRequestReceivedAlert else { return }
         DispatchQueue.main.async {
             let alert = UIAlertController(title: "Device Link Request Received", message: "Open the device link screen by going to \"Settings\" > \"Devices\" > \"Link a Device\" to link your devices.", preferredStyle: .alert)
@@ -76,4 +79,10 @@ class BaseVC : UIViewController {
             self.present(alert, animated: true, completion: nil)
         }
     }
+
+    @objc internal func handleAppModeChangedNotification(_ notification: Notification) {
+        if hasGradient {
+            setUpGradientBackground() // Re-do the gradient
+        }
+    }
 }

Signal/src/Loki/View Controllers/HomeVC.swift

@@ -348,6 +348,13 @@ final class HomeVC : BaseVC, UITableViewDataSource, UITableViewDelegate, UIScrol
         pathStatusViewContainer.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(showPath)))
         navigationItem.rightBarButtonItem = UIBarButtonItem(customView: pathStatusViewContainer)
     }
+
+    @objc override internal func handleAppModeChangedNotification(_ notification: Notification) {
+        super.handleAppModeChangedNotification(notification)
+        let gradient = Gradients.homeVCFade
+        fadeView.setGradient(gradient) // Re-do gradient
+        tableView.reloadData()
+    }
     
     // MARK: Interaction
     func handleContinueButtonTapped(from seedReminderView: SeedReminderView) {

Signal/src/Loki/View Controllers/SettingsVC.swift

@@ -49,6 +49,13 @@ final class SettingsVC : BaseVC, AvatarViewHelperDelegate {
         result.addTarget(self, action: #selector(copyPublicKey), for: UIControl.Event.touchUpInside)
         return result
     }()
+
+    private lazy var settingButtonsStackView: UIStackView = {
+        let result = UIStackView()
+        result.axis = .vertical
+        result.alignment = .fill
+        return result
+    }()
     
     // MARK: Lifecycle
     override func viewDidLoad() {
@@ -110,9 +117,9 @@ final class SettingsVC : BaseVC, AvatarViewHelperDelegate {
         topStackView.layoutMargins = UIEdgeInsets(top: 0, left: Values.largeSpacing, bottom: 0, right: Values.largeSpacing)
         topStackView.isLayoutMarginsRelativeArrangement = true
         // Set up setting buttons stack view
-        let settingButtonsStackView = UIStackView(arrangedSubviews: getSettingButtons() )
-        settingButtonsStackView.axis = .vertical
-        settingButtonsStackView.alignment = .fill
+        getSettingButtons().forEach { settingButton in
+            settingButtonsStackView.addArrangedSubview(settingButton)
+        }
         // Set up stack view
         let stackView = UIStackView(arrangedSubviews: [ topStackView, settingButtonsStackView ])
         stackView.axis = .vertical
@@ -288,6 +295,17 @@ final class SettingsVC : BaseVC, AvatarViewHelperDelegate {
             }, requiresSync: true)
         }
     }
+
+    @objc override internal func handleAppModeChangedNotification(_ notification: Notification) {
+        super.handleAppModeChangedNotification(notification)
+        settingButtonsStackView.arrangedSubviews.forEach { settingButton in
+            settingButtonsStackView.removeArrangedSubview(settingButton)
+            settingButton.removeFromSuperview()
+        }
+        getSettingButtons().forEach { settingButton in
+            settingButtonsStackView.addArrangedSubview(settingButton) // Re-do setting buttons
+        }
+    }
     
     // MARK: Interaction
     @objc private func close() {
@@ -297,6 +315,7 @@ final class SettingsVC : BaseVC, AvatarViewHelperDelegate {
     @objc private func switchAppMode() {
         let newAppMode: AppMode = isLightMode ? .dark : .light
         AppModeManager.shared.setCurrentAppMode(to: newAppMode)
+        NotificationCenter.default.post(name: .appModeChanged, object: nil)
     }
 
     @objc private func showQRCode() {

SignalMessaging/Loki/Redesign/Style Guide/Gradients.swift

@@ -19,7 +19,11 @@ public final class Gradient : NSObject {
         let layer = CAGradientLayer()
         layer.frame = UIScreen.main.bounds
         layer.colors = [ gradient.start.cgColor, gradient.end.cgColor ]
-        self.layer.insertSublayer(layer, at: 0)
+        if let existingSublayer = self.layer.sublayers?[0] {
+            self.layer.replaceSublayer(existingSublayer, with: layer)
+        } else {
+            self.layer.insertSublayer(layer, at: 0)
+        }
     }
 }
 

SignalServiceKit/src/Loki/Utilities/Notification+Loki.swift

@@ -2,6 +2,7 @@
 public extension Notification.Name {
 
     // State changes
+    public static let appModeChanged = Notification.Name("appModeChanged")
     public static let blockedContactsUpdated = Notification.Name("blockedContactsUpdated")
     public static let contactOnlineStatusChanged = Notification.Name("contactOnlineStatusChanged")
     public static let groupThreadUpdated = Notification.Name("groupThreadUpdated")
@@ -28,6 +29,7 @@ public extension Notification.Name {
 @objc public extension NSNotification {
 
     // State changes
+    @objc public static let appModeChanged = Notification.Name.appModeChanged.rawValue as NSString
     @objc public static let blockedContactsUpdated = Notification.Name.blockedContactsUpdated.rawValue as NSString
     @objc public static let contactOnlineStatusChanged = Notification.Name.contactOnlineStatusChanged.rawValue as NSString
     @objc public static let groupThreadUpdated = Notification.Name.groupThreadUpdated.rawValue as NSString